Condensed Review Flashcards
What phases are Cdks present in the cell cycle?
All phases
What does centromere protein A (CENP-A) do?
recruits proteins to the centromere from the kinetochore
What do cyclins do and how do they do it?
regulate cell cycle progression by activating Cdks
What does the Gap 2-M phase checkpoint do?
checks DNA replication status and the integrity of the DNA.
When is mitosis promoting factor (MPF) activated?
When it is singly phosphorylated
What does the Ubiquitin-proteasome pathway controls?
the degradation of regulatory proteins
What is the phosphorylation of condensin done by? What is the phosphorylation of condensin required for?
it is done by M-cyclin-M-Cdk. It is required for chromosome condensation.
Cyclin synthesis and degradation, Cdk phosphorylation, and Cdk dephosphorylation all do what?
regulate mitotic Cdk activity
After DNA replication, the sister chromatids are held together by what?
Cohesins
Condensins assemble or associates with DNA when what?
phosphorylated by M-Cdk
DNA damage causes elevated levels of p53, what does this result in?
the expression of Cdk inhibitor proteins such as p21
What does S-Cdk do to ensure that DNA replication only happens once?
it phosphorylates cdc60 and inactivates it.
Progression through the cell cycle requires a ____ to bind to a ____?
cyclin, Cdk
The binding of a cyclin to a Cdk is also required for what?
Cdk enzymatic activity
During anaphase, why are sister chromatids separated?
because securins are degraded and destroyed due to ubiquitination by APC
The Gap 1 DNA damage checkpoint inhibits cyclin-Cdk complexes by what?
p21 (p21 is a protein that muffles signaling from the cyclin-Cdk complex)
The concentration of M-cyclin falls where because of ubiquitination and degradation?
at about the end of M phase
The retinoblastoma (Rb) protein blocks cells from entering the cell cycle by doing what?
inhibiting cyclin transcription
M-Cdk stimulates or promotes the activity of APC. The APC promotes the degradation of proteins that regulate M phase and it inhibits M-Cdk activity.
just memorize this one idk what to make the question out of this.
Phosphorylation of mitotic Cdk by the inhibitory kinase (Wee1) makes the Cdk inactive, inhibiting the Cdc25 phosphatase will delay the G2/M transition and the activating phosphatase (Cdc25) removes the two phosphates from mitotic Cdk that were added by Wee1, so that M- Cdk will be active.
just memorize this one idl what to make the question out of this.
In what phase are sister chromatids separated
Anaphase II
When does meiosis most resemble mitosis?
In meiosis II
What is the result of Meiosis I
Two haploid cells
Meiosis includes ___ round of replication and ___ nuclear division(s)
one, two
What does meiosis produce?
Four haploid cells, with a random mix of maternal and paternal chromosomes
In what phase of prophase I does the synaptonemal become fully developed?
pachytene
During homologous recombination (meiosis), chiasmata hold homologous chromosomes together until when?
Until the cell is ready to divide
Why do different gametes end up with different alleles of each gene?
because segregation of homologs is random
What do sexually reproducing organisms use sexual reproduction for?
to alter and to merge haploid cells to generate diploid cells
What does the formation of a bivalent ensure?
all four sister chromatids remain together until the cell is ready to divide
Do the paternal and maternal chromosomes pair with each other before or after lining up at the metaphase plate?
before
Name some advantages of sexual reproduction
unicellular organisms have an increased ability to adapt to harsh environments, reshuffles genes, can speed up elimination of deleterious alleles.
What is a zygote?
a fertilized egg
What is the difference between apoptosis and necrosis
Necrosis=cells swell and burst, apoptosis= cells shrink and condense
what is apoptosis?
programmed cell death, an intracellular suicide program
What can promote apoptosis?
release of cytochrome c into the cytosol from mitochondria
what is mitochondrial division mechanistically like?
Prokaryotic cell division
The mitochondrial outer membrane in permeable to molecules with a molecular mass as high as?
5000 daltons
What does the mitochondrial inner membrane contain?
transporters for ATP molecules
What does the mitochondrial intermembrane space contain?
proteins (cytochrome c) that are released during apoptosis
The mitochondrial matrix contains what?
enzymes required for the oxidation of fatty acids
What is glycolysis, what is it used for and where does it occur?
It is an anaerobic process used to catabolize glucose and it occurs in the cytosol.
What is the final metabolite produces by glycolysis
pyruvate
What is the net number of activated carrier molecules produced from one molecule of glucose?
2 molecules of ATP and 2 molecules of NADH
What does the conversion of pyruvate to acetyl CoA in aerobic cell respiration include?
production of carbon dioxide
What happens in oxidative phosphorylation?
a phosphate group is added to ADP to produce ATP
What is the process oxidative phosphorylation,
molecular oxygen serves as a final electron acceptor, FADH2 and
NADH become oxidized as they transfer a pair of electrons to the electron-transport chain and the electron carriers in the electron-transport chain toggle between reduced and oxidized states as electrons are passed along. (Glycolysis (glucose to pyruvate) is not the same as oxidative phosphorylation)
What things act as a proton pump in in the electron transport chain?
NADH dehydrogenase, cytochrome c reductase and cytochrome c oxidase
What is cytochrome c oxidase required for?
to combine the pair of electrons with molecular oxygen.
